1. Field of the Invention
This invention relates to a neutral control device of an automatic transmission, more particularly, a device for preventing the slipping down of a vehicle stopped on an upward slope.
2. Description of the Prior Art
Generally, in the case where an automatic transmission is left as it is in a running range when the vehicle is stopped, engine vibration is transmitted to a vehicle through a motive power transmitting channel or engine load acts continually, with the result of wasteful fuel consumption.
In the light of the above problem, Japanese Patent Application Laid Open Gazette No. 59-34051, for example, discloses a device wherein when the vehicle is stopped, the transmission is controlled to be placed in "neutral" while a brake pedal is stepped on so as to prevent engine vibration from being transmitted to the vehicle, and also to save on fuel consumption because of the no-load state.
According to the above device, a transmission is controlled to be placed in "neutral" only while a brake pedal is stepped on and therefore movement of a vehicle will hardly take place so long as the brake is working, but when a driver releases the brake at starting, especially on a sloped road, the transmission is shifted from the "neutral range" to the "running range" by this releasing operation and formation of the starting gear position begins. However, until such gear position is formed, a vehicle will gradually go down the upward slope by its own weight.